1. Field of the Invention
The present invention relates to a composition for the cosmetic or dermatological treatment of imperfections or disorders of the skin, including the scalp. It relates more particularly to a composition of this type including at least one active substance conveyed by at least two separate types of lipid vesicles.
The invention also relates to a use of this composition for the cosmetic treatment of the skin, to the use of this composition for the preparation of an ointment intended for the dermatological treatment of the skin and to a process of cosmetic treatment of the skin.
2. Discussion of the Background
Many examples are known of cosmetic or dermatological compositions intended for the treatment of the skin, which have one or a number of active substances that are suitable for the treatment of the skin, encapsulated in lipid vesicles or spherules (also called liposomes).
Lipid vesicles or spherules are intended to mean particles made up of a membrane consisting of one or a number of concentric leaflets, these leaflets comprising one or more bimolecular layers of amphophilic lipids encapsulating an aqueous phase. The aqueous phase may contain water-soluble active substances and the bimolecular layers of amphophilic lipids may contain lipophilic active substances.
These spherules generally have a mean diameter of between 10 and 5,000 nanometres.
Among the many published documents relating to this matter, it is possible to mention French Certificate of Addition 2408387, which describes a composition based on aqueous dispersions of ionic or nonionic lipid spherules encapsulating at least one active substance. More precisely, this document describes compositions containing at least two dispersions of spherules containing different active substances, with the aim of obtaining a mixed system. That is to say, a system where a first dispersion of spherules containing a first class of active substance is used in combination with a second dispersion of spherules containing another class of active substance, which enables both categories of substances to act simultaneously at the time of the treatment and possibly to obtain a synergistic effect that would not be produced if these two classes of substances were made to act successively and separately.
The inventors have has now developed a cosmetic or dermatological composition permitting the simultaneous action of two different active substances and, furthermore, enabling these active substances to act in different regions of the skin, that is to say in the surface layers and in the deep layers of the skin, thereby very markedly enhancing the effectiveness of these compositions and the complementary or synergistic effect of the active substances used.
The inventors have also developed a cosmetic or dermatological composition enabling the same active substance to act simultaneously in the surface layers and in the deep layers of the skin, ensuring a more complete and therefore more effective treatment of the disorder from which it suffers.
Now, there are many situations in which skin disorders involve both a threat to the surface layers of the skin and accompanying change in the deeper layers of the latter.
It is well known that the skin consists of surface layers, the stratum corneum, and of deep layers, the living epidermis and the dermis. However, in the prior art it was not known to deliver such an active substance specifically into the surface layers and, simultaneously, the same or some other active substance into the deep layers.